How to sprout citrus seeds?

[Pandan]

I've got some citrus seeds in the fridge, I've treated them with a light copper based fungicide and soap wash.

How should I go about sprouting them in a way that minimizes problems as I've noticed major issues in regards to molding when Ive tried citrus in the past

[pagnr]

I think it was covered by a few people here
https://tropicalfruitforum.com/index.php?topic=46266.0

Good hygiene is also important in seed collection, such as picking fruit before it falls to ground,
extracting seed before fruit goes off.
Cleaning seed thoroughly of juice and pulp etc,
using new zip bags for seed,
sterilising tools and strainers with boiling water between seed types/lots.
Working in a clean area, i.e. kitchen when wife not home !!!
Cleaning your hands between seed lots.
Cleaning/sterilizing the the peel of any older, fallen, mouldy fruit etc before getting to the seeds.

I had some mould  problems with long term storage, when saving Autumn seed for Spring planting.

This year for Citrus I simply used the gel based hand sanitiser we are all now familiar with. 5 to 10 mins in the gel then rinse thoroughly before storage in bags.
The seed were placed on clean paper kitchen towel. Wetted, then water squeezed out to damp.
The moisture level should be watched in storage. Any excess moisture squeezed out.
Also check the seed bags regularly.
If any mould developed, I repeated the rinsing / gel process, and replaced the zip bag and paper towel.
Often the mould seemed to be on the paper towel, more than the seed.

I haven't had much problem with mould after planting, I delay till soil mix is warmer, use a free draining mix in taller pots.
Techniques that keep the mix moist, but surface drier and reduce watering frequency could help.
I now use a plastic cover on Citrus germination pots, this gives high humidity, but less frequent watering.
Soilless propagation mixes should reduce pathogens, as should heat treating the mix components ( usually not with fertiliser added ).
Heat could be steam, boiling, solarisation.

Probably the first question should be where is the mould coming from ??
On the seed ? From the pot mix ?? (compost organisms ??) From the greenhouse area or general environment ??

[Pandan]

I think it was covered by a few people here
https://tropicalfruitforum.com/index.php?topic=46266.0
-
Probably the first question should be where is the mould coming from ??
On the seed ? From the pot mix ?? (compost organisms ??) From the greenhouse area or general environment ??

great link, thank you!

and in regards to the 2nd question thats what I can't figure out. I have terrible luck with poncirus seeds in particular but have OK success with most citrus and have had pretty good success with almost any other family, generally few mold or damping off issues.

[Millet]

he University of California at Riverside, recommends a through seed washing followed by a soak in 125F water for 10 minutes.  Then let seed dry.

[sc4001992]

I follow instructions as Millet mentions but I don't let it dry. So when I eat a new citrus that tastes great, I just thoroughly clean them, then leave them in a small plastic cup with water until I feel like planting the in the soil. Seems to work great for my pomelos and grapefruits. I have a nice 4ft sumo from a fruit that I found 3 seeds three years ago.

Millet, do you know why they suggest letting the seeds dry? My seeds do dry out if I forget to change the water in the cup and it evaporates.

[Pandan]

After a bit of reading I think I may try a fungicide seed treatment

https://crops.extension.iastate.edu/encyclopedia/fungicide-seed-treatment

I'm thinking of using captan if I can find it for a good price.
https://davesgarden.com/community/forums/t/1123590/#b

[pagnr]

Drying the Citrus seed removes excess moisture, ( reduces mould bacteria growth ).
It also delays germination until planted in seed boxes.
For large lots of rootstock seed, germination needs to be delayed for shipping, planting etc, otherwise they will be sprouting pretty soon.
Generally it means spread out and air dried, for a few hours to overnight.

[sc4001992]

Pagnr, that sounds right. I just change the water out in my small plastic cup with seeds in them and so I must be washing out the mold/bacteria growth. I do see some seeds that go bad in the water cup. I also noticed that pummelo and grapefruit seeds have much harder shell and seems to not get the problems like the lemon, mandarin, and orange seeds.

I just planted a handful of my pummelo seeds with no special treatment except this water cup method and they seem to all be doing well and growing. I'll post a photo later to show these healthy seedlings. Now I don't know what to do with hundreds of new seedlings.

[Vlad]

I peal off the outer layer and place them in moist paper towel in sandwich bag. Incubate at room temp. Have had no mold growth

[sc4001992]

Vlad, that sounds good, but a lot of work if you have hundreds of seeds. Since I have some many fruits, if I can get 50% of the seeds to grow out, that is still more than I know what to do with the new plants.

[pagnr]

Peeling the seed coat and planting point down is used to prevent bench root in rootstocks. Bench root is anything other than a straight shoot up, root down seedling.
A drying seed coat at planting can cause the root to circle before heading down. Even an L shaped bend in a Citrus rootstock seedling can cause a snapping weakness in young trees.
I don't peel the seed coats so far, but I do store them in the paper towel / zip lock. Some in the fridge to delay, some in a warm environment to sprout.